Field
Embodiments of the present disclosure relate to apparatus and methods for processing semiconductor substrates. More particularly, embodiments of the present disclosure relate to apparatus and methods for stabilizing substrate temperature during high temperature processing.
Description of the Related Art
In some semiconductor processes, temperature of the substrate being processed is usually maintained by a heat sink, such as a large thermal conductive body, attached to the substrate support. Traditionally, heat sinks used in high temperature physical vapor deposition (PVD) are not actively cooled because temperatures in these PVD chambers are so high that traditional coolants would boil in the heat sink cooling channel. Since traditional PVD recipes usually include fairly short deposition time, e.g. in the order of 10s of seconds, heat load on the substrate can be dissipated by the relatively large heat sink below the substrates. However, as the time of deposition extends in PVD recipes, for example into the range of hundreds of seconds to thousands of seconds, non-actively cooled substrate support cannot dissipate the heat load on the substrate being processed resulting in process drift and degradation of the film being deposited. GALDEN® heat transfer fluid or other similar high boiling point coolants have been used in cooling the substrate support for long lasting PVD processes. However, these high boiling point coolants are not only expensive but also prone to thermal decomposition and may become corrosive and/or release harmful gases, such as HF and fluorophosgene.
Therefore, there is a need for an improved apparatus and methods for controlling substrate temperature for high temperature PVD processes.